2 minutes quicker than the National Express coach to Stansted (sold from £21.30), for up to £1.50 more. And no booking needed.
Elizabeth line and Stansted Express to Stansted
ElizabethStansted Express · Transport for London and Greater AngliaPickup, hours & luggage
Boards at. Heathrow Terminals 2 & 3 or Terminal 4 rail station; changing at Liverpool Street
£22.80 by contactless for the whole trip, on TfL's fare finder, and £27.80 on weekdays from 06:30 to 09:30 and from 16:00 to 19:00. Oyster does not work at Stansted.
Luggage. Racks at the ends of the Elizabeth line carriages; racks at the ends of the Stansted trains.
Hours. Monday to Saturday from Terminals 2 and 3. On Sundays the first is 07:39.